MOSCOW, Maine -- It's a dinosaur of the Cold War: a 3-mile-long radar system
designed to detect Soviet bombers screaming across the Atlantic.

The Over-The-Horizon Backscatter Radar, often described as the world's largest
radar, was developed over 25 years for $1.5 billion and occupies an area
nearly twice the size of New York's Central Park.

When operational, it could monitor a massive swath of ocean and warn of threats
nearly 2,000 miles away.

Built in both Maine and Oregon, the radars picked up readings as far as 1,700
miles off both coasts. But the military is scrapping the wire-and-steel
monoliths, along with outdated warhead silos and other relics of the arms
race.

''The world changed," said Steve Hinds, manager of the OTH-B radar program
at Air Combat Command, which oversees US fighter and bomber wings. ''This
will not be used for what it was intended. Ever."

The backscatter radars bounced a beam off the ionosphere, which sends a scattered
signal back to the Earth's surface. They were so sensitive they could even
detect changes in ocean currents, a useful tool for the National Oceanic
and Atmospheric Administration, which debated acquiring the radars for research.

The radar in Maine, nestled in the woods in a place that bears little resemblance
to the Russian capital for which the nearby town was named, operated for
just one year in the early 1990s before it was mothballed.

Military officials had planned to install additional over-the-horizon radars
to oversee other hemispheres, but only installations in Maine and Oregon
were built before the program was scrapped in favor of more advanced Navy
technology.

The Air Force maintained the ability to restart the radars to protect against
a new threat before beginning to dismantle the facilities late last year.
Other agencies also wondered if they could use the radar to detect ocean-bound
drug shipments.

David Winkler, a historian with the Naval Service Museum, studied the radars
for a report to the Defense Department on the legacy of the Cold War in the
late 1990s. They were designed to deter countries with nuclear capabilities,
he said.

''They are out there to deter anybody who has a bad day and decides to launch
against us," Winkler said. ''But who are we deterring now? Al Qaeda?"

While many Cold War military installations have closed in the last decade
-- some military analysts expect that to weigh heavily in this year's base
closings -- decommissioning the radar marks to some a change in homeland
defense.

Winkler said the decision to tear down the radar is the last move in a shift
from a Cold War posture to one more suited to keeping even the possibility
of conflict off shore.

But not everyone shares the assessment that the radar is useless.

John Pike, a military specialist with GlobalSecurity.org, said he is puzzled
by the decision to dismantle the backscatter radar during an age when nuclear
proliferation remains a concern and countries like Iran and North Korea are
developing long-range nuclear warheads.

''North Korea's missiles may or may not be able to get to the United States
if they were launched from North Korea. But they could if they were launched
by tramp steamers 1,000 miles off the coast," he said.

Military officials counter that it's not defense they are leaving behind,
it is a matter of how they are going to defend. New radar technology, including
a relocatable version of the backscatter radar, has replaced the massive
structure.

The Air Force in the months ahead plans to begin shopping the nearly 1,200
acres to industrial clients who could lease the land.

The U.S. Air Force's over-the-horizon-backscatter (OTH-B) air defense radar
system is by several criteria the largest radar system in the world. Six
one-million-watt OTH radars see far beyond the range of conventional microwave
radars by bouncing their 5-28-MHz waves off the ionosphere, an ionized layer
about 200 km above the earth. It was developed over 25 years at a cost of
$1.5 billion to warn against Soviet bomber attacks when the planes were still
thousands of miles from US air space.

In 1970 Air Force Rome Air Development Center [RADC] engineers developed
and constructed components for a frequency modulation/continuous wave (FM/CW)
radar capable of detecting and tracking objects at over-the-horizon ranges.
The radar installation and evaluation was accomplished on 15 September, while
flight tests of a Beverage array antenna were completed on 30 September.
On 30 October 1970 the radar and the Beverage array were integrated and operated
as a single system for the first time.

The Department of Defense initially planned a central sector radar facing
south, and an Alaska System facing north, to complement OTH-B radars on the
east and west coast to detect enemy bombers and cruise missiles. With the
end of the Cold War the military requirement for the central-sector radar
had largely disappeared, and it was being pursued now almost exclusively
for the drug interdiction mission. The Congress found this system to be redundant
and unnecessary for this effort.

The total value of the ceiling price of that contract for the first and second
sectors of the portion of the OTH-B radar program known as the Alaskan System
was estimated at $530,000,000. The unexpected cost growth in the deployment
of the first sector of the Alaskan OTH-B system defered procurement of the
second sector of this system until at least fiscal year 1991. The main reason
for the cost growth is the high cost of construction of this type of facility
at the site selected by the Air Force. Consequently, the deployment of the
Central CONUS system was deferred at least until fiscal year 1992, with land
acquisition required no earlier than fiscal year 1991.

With the end of the Cold War, just months after their deployment, the three
OTH radars on the West Coast were mothballed, and the incomplete Alaska System
cancelled, but the three radars in Maine were redirected to counter-narcotics
surveillance. In 1994 the Congress directed the Air Force to continue operating
the East Coast OTH-B radar at no less than a 40 hour per week schedule, and
to ensure that all OTH-B tracking data was transmitted directly to DOD and
civilian agencies responsible for providing counterdrug detection and monitoring
support to law enforcement agencies. In order to utilize the full potential
of this wide-area sensor, the Congress directed DOD to (1) assist the Air
Force in linking the East Coast OTH-B radar site data directly to users,
including but not limited to the U.S. Customs/Coast Guard C3I Center, Miami;
Joint Task Force 4 Operations Center, Key West; U.S. Southern Command Operations
Center, Key West; and U.S. Southern Command Operations Center, Panama; and
(2) fully cooperate with efforts of other government agencies to utilize
the dual-use capabilities of this system for remote environmental and weather
monitoring and other purposes.

The Air Force maintains the six East Coast and West Coast OTH-B radars in
a state called warm storage, which preserves the physical and
electrical integrity of the system and permits recall, should a need arise.
It would require at least 24 months to bring these first generation OTH-B
radars out of caretaker status and into an operational status-if such a decision
to do so were made. Major upgrades costing millions of dollars would be necessary
to bring the outdated technologies up to modern standards. The incremental
cost of operating the East Coast OTH-B system for environmental research
and services is about $1.0M to $1.5M per year. The environmental monitoring
aspects of the system are unclassified. Similar coverage in the eastern Pacific
could be obtained at about the same cost.

In 1991, NOAA recognized the potential of these military relics of the cold
war for environmental monitoring and asked the Air Force's permission to
look at the part of the radar echo that the Air Force throws away -- the
ocean clutter. NOAA's tests showed that this clutter can be processed to
extract ocean surface wind direction over huge, data-sparse ocean areas --
vital information that affects climate and the ocean's circulation. Tropical
storms and hurricanes were tracked, and a system for delivering radar-derived
winds to the National Hurricane Center was developed. The combined coverage
of the six OTH-B radars is about 90 million square kilometers of open ocean
where few weather instruments exist. Recent tests have also demonstrated
OTH radars ability to map ocean currents.